HALLEY'S COMET. 



171 



HALLEY'S COMET. 



FOR the civil and political historian the past alone has existence the pres- 

 ent he rarely apprehends, the future never. To the historian of science it is 

 permitted, however, to penetrate the depths of past and future with equal clear- 

 ness and certainty ; facts to come are to him as present, and not unfrequently 

 more assured than facts which are passed. Although this clear perception of 

 causes and consequences characterizes the whole domain of physical science, 

 and clothes the natural philosopher with powers denied to the political and 

 moral inquirer, yet foreknowledge is eminently the privilege of the astronomer. 

 Nature has raised the curtain of futurity, and displayed before him the succes- 

 sion of her decrees, so far as they effect the physical universe, for countless 

 ages to come ; and' the revelations of which she has made him the instrument, 

 are supported and verified by a never-ceasing train of predictions fulfilled. He 

 " shows us the things which will be hereafter," not obscurely shadowed out in 

 figures and i-n parables, as must necessarily be the case with other revelations, but 

 attended with the most minute precision of time, place, and circumstance. He 

 converts the hours as they roll into an ever-present miracle, in attestation 

 of those laws which his Creator through him has unfolded ; the sun cannot 

 rise the moon cannot wane a star cannot twinkle in the firmament, without 

 bearing witness to the truth of his prophetic records. It has pleased the 

 " Lord and Governor" of the world, in his inscrutable wisdom, to baffle our 

 inquiries into the nature and proximate cause of that wonderful faculty of intel- 

 lect that image of his own essence which he has conferred upon us ; nay, 

 the springs and wheelwork of animal and vegetable vitality are concealed from 

 our view by an impenetrable veil, and the pride of philosophy is humbled by 

 the spectacle of the physiologist bending in fruitless ardor over the dissection 



NOTE. A portion of the matter which forms my lectures on Comets, was formerly contributed 



by me, on various occasions, to the Edinburgh Review, and other leading periodicals in England ; ( 



and a part was included among the additions to the late edition of Arago's Lectures, edited by me J 



in America j 



